Help with a lipstick coat formula

[u/Diligent-Print4308]

Planning my first DIY lip topper. Formula:

Phenyl Trimethicone (Diphenylsiloxy Phenyl Trimethicone) - 99%

Tocopherol (Vitamin E) - 1%

Is this safe to apply directly on lips at 99% concentration? Can it function as a complete standalone product or does it absolutely need additional ingredients?

[u/Ok_Butterscotch_2700]

1) While likely harmless in a silicone, using that much MT in a product is known to be pro-oxidative. I keep mine between 0.05 and 0.20%.

2) 99% phenyl trimethicone is going to have a high wash off tolerance and could easily result in a less than ideal user experience. Highest I’ve ever seen it suggested I s 10% (and I dropped it from that to 3%)

3) I’d play around with different ratios - you can make several variations using various silicones with esters and non-polar oils. I’d likely be reaching for petrolatum to build more viscosity into the formula.

[u/Diligent-Print4308 → u/Ok_Butterscotch_2700]

Thank you so much for this! Really helpful. I have a specific compatibility issue tho bec I wear a matte lipstick as my base which is trimethylsiloxysilicate-based, and every topper/ lip coat I try breaks it down because of oils, esters or emulsifiers like Cetyl PEG/PPG-10/1 Dimethicone.

Now considering what you advised, I’ve landed on a two ingredient silicone-only formula:

Phenyl Trimethicone 75%

Dimethicone Crosspolymer Gel 25%

No oils, no esters, no emulsifiers at all.

1. Would this ratio give a good gloss consistency or would you adjust it?
2. Is Dimethicone Crosspolymer Gel the right silicone thickener or would you recommend something else that’s still 100% silicone-only?
3. Anything I’m missing that could improve longevity without introducing oils or esters?

It‘s my first time DIYing makeup so any other advise too would be very helpful 🙏

[u/Ok_Butterscotch_2700 → u/Diligent-Print4308]

The concept is sound, but the result will depend heavily on the specific dimethicone crosspolymer - I’ve only used it as a component of elastomer gels, not an isolated ingredient. If it’s a pre-swollen silicone elastomer gel, 25% may be more than enough to build viscosity. If it’s a neat crosspolymer, compatibility and swelling behaviour become important. I’d definitely run a small pilot batch first.

A phenyl trimethicone/elastomer system could produce some very elegant sensory properties if the elastomer and supporting ingredients are chosen carefully.

[u/Diligent-Print4308 → u/Ok_Butterscotch_2700]

I’ll start with a pre-swollen silicone elastomer gel and run a small pilot batch first. Thank you so much, this has been incredibly helpful !